Pak- the Irken life source. The Pak rests on the back of an Irken, silver with three colored spots, one on top two on bottom. The Pak stores memories and background information about the Irken as well as emotions and thoughts. It has to be recharged every two months before it runs out of power. If the Pak is popped off, the Irken must re-attach it or they can only survive for ten minutes before they die.
The Pak is also a constant supply of energy, and is the reason Irkens never sleep and rarely eat.

Little known fact:
All of the information retreived by the Pak is fed into the Collective Memory, which is located on Irk and holds every ninch of information about every Irken and even the history of Irk itself.

On Earth, Tak disguised her Pak as a common student backpack to keep the humans (and Zim) none-the-wiser about her true identity.

The Urban Dictionary T-Shirt

An extremely common misspelling of the word, "pack".
This misspelling is even made by large corporations who ought to know better.

{Brad}: Hey Kestra, I just zipped open this week's Val Pak coupons and found coupons for 65% off Wrigley's Plen-T-Pak gum and 57% off those Freez Paks!
{Kestra}: Great Brad, let me stuff those fuckers in my purse and run to the store straight away!!!

The Urban Dictionary T-Shirt

To strike or otherwise beat with or without an implement of beating. Originally started as a parody of the visual 1960s Batman fight sound effects. Imagine the word "PAK" in bright letters when you strike someone or something.